I am participating in a design competition based on lunar In-Situ Resource Utilization (ISRU). A key component of this design is transporting regolith-mined water from a water extractor in a Permanently-Shaded Region (PSR) to a delivery site. The delivery site is approximately 4 km horizontal distance and 450 m above the water extractor.
Ground temperature inside this PSR is between 40 and 100 Kelvin, with the possibility of using some heating power to warm components.
A thrower-catcher system has by far the lowest power consumption of all considered water transport options, except for maybe an (extremely heavy) 4.5 km rigid pipe. The water would be in homogenous ice form, probably a cube or sphere for handling simplicity.
From kinematics, initial velocity would need to be 174 m/s at a minimum. That speed would require a huge trebuchet, but motors can be used to augment a much smaller trebuchet ("flywheel trebuchet").
Has anyone calculated the possible accuracy of using a space-grade trebuchet in vacuum? How about other thrower options such as a ballista, compressed gas cannon, chemical propellant cannon, or railgun?
- Ice sublimates in vacuum, so transport either needs to be quick (<2 minutes?) or include some sort of container/wrapper around the ice.
- Let’s go ahead and set a 3000 kg mass limit for all components besides regolith and water ice.
- A 20x20 meter target (net?) is somewhat feasible to construct.
- Wasting ice is tolerable (up to ~90% wasted).
FYI for people who find this answer while researching for the same competition: